Telephone-circuit signal



(No Model.)

M. A. EDSON. TELEPHONE CIRCUIT SIGNAL.

Patented Nov. 26, 1895.

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7k flaw aablb AN DREW BJSRMIAM HOTULITHQWASHINGTDUIDL UNITED STATES PATENT OFFICE.

MARK A. EDSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS.

TELEPHONE-CIRCUIT SIGNAL.

SPECIFICATION forming part of Letters Patent No. 550,260, dated. November 26, 1895.

Application filed May 20, 1895. Serial No. 549,966; (No model.)

T at whom it may concern.-

Be it known that I, MARK A. EDsoN, residing at Chicago, in the county of Cook and State of Illinois, have invented certain Improvements in Telephone-Circuit Signals, of

which the following is a specification.

This invention relates to the signal-receiving apparatus employed in connection with the switchboards of a telephone central office IO by means of which the customer at a sub.-

station may indicate a wish to communicate with the operator and initiate a call or whereby the operators at the different sections at the central station may signal one another.

The invention is an improvement in that class of signaling apparatus in which a small glow-lamp is used as the signal to attract attention, the same bcin g located in a conspicuous position to indicate or illuminate any prearranged signal or code of signals.

The invention relates, mainly, to the structure of the signal-receiving device, and comprises the combination, in a single appliance or instrumentality, of a relay whose magnet- 2 5 izing-coil is in the main circuit and Whose core when excited attracts a tilting-disk armature and a glowdamp in a local circuit controlled by the said relay by means of the said armature, both being inclosed in the same 0 casing. The local circuit contains, of course,

a suitable current-generator, as a voltaic battery.

The signal is contained in a cylindrical casing and is arranged to present one end only 3 5 to the observer, the main body of the casing being concealed. It includes a coil of fine insulated Wire upon an insulating-bobbin, which surrounds a tubular iron core and is adapted for inclusion in the main circuit. In the center of the tubular core is an insulated rod, which projects from each end of the bobbin. The bobbin is inclosed in a magneticmetal sheath with chambers at each end. The chamber at the outer end is formed of a nonmagnetic cap and incloses a movable tilting disloarmature in the shape of a truncated cone standing on its edge and provided With suitable means for adjustment, against which it normally rests. The chamber at the other end incloses a small incandescent or glow lamp, the filament of which is included in a normally-open local generator-circuit formed in part by the rod in the center of the helix and the outer metal casing, and the said local circuit is adapted to be closed by the movable armature and thereupon make operative the lamp and illuminate any distinctive device in front thereof.

For a detailed description of the invention reference is made to the drawings, in which--- Figure 1 is a horizontal section through a signal appliance embodying my invention. Fi 2 is an end view of the same. Figs. 3 and 4. are respectively sections on lines 00 m and g y of Fig. 1. Fig. 4 is a perspective view of the movable armature, and Figs. 5 and 6 illustrate the working of the automatic signal.

A represents the signal as a complete device, which comprises an electromagnetically-op- 7o erated relay R whose helix 1 is of line wire to be included in the main circuit L, as shown in Figs. 5 and 6, and a glow-lamp G in the local circuit on, controlled by said relay. The helix is wound upon a bobbin 2, ofinsulating 7 5 material, in the center of which is a tubular soft-iron core 3, extending from the plug 33, to which is screwed the cylindrical case 10, which is made of magnetic metal, preferably iron, and which extends over the helix 1 and has the non-magnetic metal cap 6 secured to its end to form a chamber 34. A rod of any metal or alloy, such as brass, is placed Within the core and insulated therefrom by a rubber tubej. It projects beyond the bobbin into 8 5 the chamber 3% at one end and at its other end projects into a cavity in the plug 9 is a movable tilting soft-iron disk armature shaped as a truncated cone, Which rests upon the floor of the cap 6 by the edge of its 0 base, its lower inner surface bearing upon the end of the metal tube 10 and being held in place and made adjustable by the adjustingscrew 8. A great advantage of this construction is that the armature resting on its sharp 5 edge 011 the internal periphery of a circle c011- siderably larger than itself is almost frictionless.

11 is a cylindrical tube, which may be of any suitable material impervious to light-rays, in- 1 0o closing the end of the plug and secured thereto by the screw 22, which also holds in place the insulating terminal block 21. A short extension-tube 12 is inserted in the end of the tube 11, forms therewith a front chamber 35, and has a piece of ground glass 13 or other transparent or translucent substance fitted in its end, this being provided with any suitable symbol or distinctive indicating device, as a letter or number, painted or attached to its inner surface, as in Fig. 2.

14 is an incandescing or glow lamp in the chamber 35, provided with a screw-base 19 to fit a screw-socket 36 of non-conducting material, the said lamp-base supporting the filament-terminals 18 and 16, which are respectively in contact with the front end of the rod -and the ring 20, which is secured to the insulation 36 at the bottom of the cavity. The ring 20 is connected by the wire 17 passing through the insulati11gblock with one pole of a generator Z) in a local circuit, including the armature 9 and its front contact-stop viz., the rear end of the rod 5.

The other pole of the generator is connected with the casing by wire 37. A local circuit m is thus formed from one pole of the generator I) ,through the wire 37, to the casing 10, to the lower edge of the armature 9, to rod 5, filament-terminal 16, through the filament to terminal 18, to ring 20, and, finally, through wire 17 to the other pole of the generatorb.

Fig. 1 represents the signal as projecting through a partition 23, to which it is secured by one or more brackets 39. The main circuit wires and 51, as well as those of the local circuit, may connect, as shown, through the block 22.

Figs. 5 and 6 show diagrammatic sections of the signal, and the formerfigure illustrates the operation of the signal by pressing the key it at station B to its anvil, thereby causing current from the generator cl to energize the helix 1 of the signal at station 0, magnetizing the core and attracting the armature 5 thereto, so as to form a connection between the end of the rod 5 and the end of the tube 10 to close the local circuit m of the generator b to bring about the illumination of the signal-lamp 14:, the glow of which is seen at the window 13, and if a symbol is painted, placed, or engraved thereon in front of the glowing-filament it will appear while the filament is incandescent and disappear when the controlling or main circuit, and consequently the local circuit, is opened.

Fig. 6 illustrates the method of closing the circuit of the generator d by raising the telephone 2? from its hook-switch h atatelephonesub-station B in a manner well understood to energize the helix 1 and cause a signal to dis play itself at a central station 0.

If desired, the same battery as is used to excite the main circuit L or a portion thereof may be utilized in the establishment of a local-circuit current.

In the drawings I have indicated earth-coni-' pleted main circuits; but it is obvious that my signal may be associated with metallic circuits without changing its mode of operation.

I claim 1. Inacompound switchboard or telephone signal, the combination with a plug, of an incandescent or glow signal lamp secured in one side of said plug, a local circuit including said lamp and an electro-magnet for controlling said local circuit comprising a core extending from the other side of the plug, an exciting helix and an armature at the outer end of saidhelix, substantially as described.

2. An electro-magnetic relay comprising an electro-magnet with a central core, an iron casing, an interposed exciting helix, and a tilting disk armature resting on its edge in front of said core, substantially as described.

3. An electro-magnetic relay comprising an electro-magnet having a central iron core and an iron casing forming its poles; and an interposed exciting helix; a tilting armature having a thin edge resting upon the casing pole and extending in front of the core pole; and means for adjusting the position of said armature, substantially as described.

4. A compound switchboard or telephone signal, combining in a single appliance an electro-magnetic main circuit relay, having a disk armature in the form of a truncated cone, and resting by the edge of its base on a curved support of greater radius than that of said base; an incandescing or glow lamp in a local circuit controlled by the said relay; and a cylindrical casing containing both; substantially as described.

5. The combination in a telepone signal appliance, of an electro-magnectic main circuit relay havinga tubular iron core, an iron shell, an interposed exciting helix; an insulated metal rod passing through the said tubular core and projecting therefrom at its polar end, and a disk armature in the form of a truncated cone resting on the edge of its base in contact with the magnet shell, mounted in front of the iron core, and adapted to be at tracted thereby, and to make contact with the rod projecting therefrom; an incandescing or glow lamp in a local circuit including said metal rod, magnet shell and armature, and controlled by said relay; and an inclosing cylindrical case for the whole, consisting of said magnetic shell, and front and rear extension chambers therefor, the said front chamber containing the said glow lamp, and being closed by a transparent or translucent window to be illuminated by said lamp, and the said rear chamber inclosing the said armature, and supporting the edge thereof 011 its interior periphery, substantially as described.

6. An electric signal consisting of an in candescin g or glow lamp in a local circuit con tained in a tube provided with a translucent end window bearing an obscured distinctive thereon, and its base extending in front of the other pole, substantially as described.

In testimony whereof I have signed my name to this specification, in the presence of 15 two subscribing Witnesses, this 10th day of May, 1895.

MARK A. EDSON.

Witnesses:

ANNA D. RAYMOND, S. E. FISHER. 

